The present invention relates generally to surgical systems and more specifically to surgical systems that control pneumatic devices.
Many microsurgical procedures require precision cutting and/or removal of various body tissues. For example, certain ophthalmic surgical procedures require the cutting and/or removal of the vitreous humor, a transparent jelly-like material that fills the posterior segment of the eye. The vitreous humor, or vitreous, is composed of numerous microscopic fibers that are often attached to the retina. Therefore, cutting and removal of the vitreous must be done with great care to avoid traction on the retina, the separation of the retina from the choroid, a retinal tear, or, in the worst case, cutting and removal of the retina itself.
Conventional vitrectomy probes typically include a hollow outer cutting member, a hollow inner cutting member arranged coaxially with and movably disposed within the hollow outer cutting member, and a port extending radially through the outer cutting member near the distal end thereof. Vitreous humor is aspirated into the open port, and the inner member is actuated, closing the port. Upon the closing of the port, cutting surfaces on both the inner and outer cutting members cooperate to cut the vitreous, and the cut vitreous is then aspirated away through the inner cutting member. This cutting action may be made using an electric cutter, but pneumatically driven probes operating at a relatively high pressure are more common.
Additionally, during typical ophthalmic procedures, air or other fluid may be introduced into the posterior chamber. This air must be of relatively low pressure (on the order of 3-4 psi). As the infusion of fluids into an eye is done at low pressures, this portion of the surgical procedure can extend for some period of time, so to protect against an unexpected loss in power, accumulation of some reserve pressure is desirable. Prior art devices have used pressure accumulators, receivers or tanks to store this reserve pressure. Such devices can occupy a great deal of space inside the surgical console and require pneumatic connection to the appropriate manifold.
Accordingly, a need continues to exist for a surgical system having a simplified, compact construction.